1. Field of the Invention
The present invention relates to an expansion anchor including a sleeve-shaped anchor body having a through-bore, an expansion region provided with longitudinal slots and a rear section provided with load application means, and an expansion member located in the through-bore and axially displaceable in the through-bore for radially expanding the expansion region.
2. Description of the Prior Art
One of the requirements, which an expansion anchor should meet, is its easy setting. A conventional anchor, the setting of which is effected by impact expansion, meet this requirement. Such impact-setted expansion anchors have a sleeve-shaped anchor body, which is formed of steel, and an expansion member which, preferably, is likewise formed of steel, and is located in a central bore tapering in a setting direction. The expansion member is axially displaceable in the central bore. For expanding the sleeve-shaped anchor body in a bore of a receiving material, e.g., concrete, brickwork and the like, the expansion member is driven into the tapering section of the central bore by impact action acting in an axial direction. However, the conventional anchor is rather expensive in manufacture. It requires a large consumption of material, and forming the tapering bore is particularly expensive.
European Publication EP-A-0171354 discloses an expansion anchor setting of which is based on the same anchoring principle and which is characterized by a simpler manufacturing. This expansion anchor has a sleeve-shaped anchor body with an anchoring region provided with longitudinal slots, and an expansion member which is formed integrally with the anchor body and is formed as a spiral body. The expansion member is located in the central bore of the anchor body and is expanded radially by being axially upset. Due to the radial expansion of the expansion member, the expansion region of the sleeve-shaped body expands, and the expansion anchor becomes anchored in the bore. The sleeve-shaped anchor body and the expansion member are formed integrally as a one-piece part from a sheet metal stamped part. While manufacturing of an anchor from a sheet metal stamped piece has certain advantages from the manufacturing point of view in comparison with manufacturing an anchor from a massive piece of material, the anchor produced as discussed above has a certain drawback which consists in that there exist a danger of the expansion element being deformed inwardly during axial upsetting. This can result in an insufficient radial expansion of the anchor body, and the anchor would not reach the required load value.
Accordingly, an object of the present invention is to modify an expansion anchor of the type described above in such a way that the above-described drawback is eliminated, and a reliable expansion of the anchor body is insured in order to reach the required load value. At that, the expansion anchor should be capable of being produced in a simple and cost-effective manner.